The Large Hadron Collider may usher
in a new era of particle physics as the world's most powerful
particle accelerator. However, the LHC has also been the victim
of numerous delays, ever since its
launch last September failed.

At launch an
electrical fault between two of the magnets reportedly caused an
arc of electricity, which in turn triggered a helium leak and
explosion. As a result, the proton tube was contaminated with
soot, and the magnets were broken off from their mountings.
Months of repairs revealed more
leaks in the vacuum of the insulating layer surrounding the
proton tube.

Now the European Center for Nuclear Research, or
CERN has declared that the repairs
are done. States CERN in a press release, "[Tests]
will initially run at an energy of 3.5 TeV per beam when it starts up
in November this year. This news comes after all tests on the
machine's high-current electrical connections were completed last
week [the week of July 27], indicating that no further repairs are
necessary for safe running."

Still, the restart
represents caution on CERN's part -- 3.5 TeV is only half of the
beam's full intended operational power. States CERN Director
General Rolf Heuer, "We've selected 3.5 TeV to start because it
allows the LHC operators to gain experience [with] running the
machine safely while opening up a new discovery region for the
experiments."

There remain concerns about whether the
device is capable of running at full power. Describes CERN:

Following the incident of [Sept. 19, 2008] that
brought the LHC to a standstill [due to a faulty magnet connection],
testing has focused on the 10,000 high-current superconducting
electrical connections like the one that led to the fault. These
consist of two parts: the superconductor itself, and a copper
stabilizer that carries the current in case the superconductor warms
up and stops superconducting, a so-called quench. In their normal
superconducting state, there is negligible electrical resistance
across these connections, but in a small number of cases abnormally
high resistances have been found in the superconductor. These have
been repaired. However, there remain a number of cases where the
resistance in the copper stabilizer connections is higher than it
should be for running at full energy.

However, CERN also says that it has tested and repaired a large
number of these faulty copper connections. It says that the
final two sectors it tested revealed no abnormalities.
Nonetheless, after all the headaches, it plans to throttle up the
17-mile long accelerator loop slowly, just in case there's still
undetected problems.

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